Parking Lot Sealant Raises Health Concerns

The United States Geological Survey (USGS) recently released an alarming study raising concerns that dust from parking lots and driveways that have been treated with coal tar sealants may pose an increased risk of cancer to nearby residents. Coal tar sealant is made from a waste product of the steel manufacturing process (created by baking coal to produce coke) and is commonly applied to asphalt parking lots and driveways in the United States to protect against cracking and water damage and to give the surface a dark black color.

Coal tar, which contains a high amount of chemicals know as polycyclic aromatic hydrocarbons (PAHs), is known to cause cancer in humans. The most dangerous and potent of the cancer causing PAHs found in coal tar is benzo[a]pyrene. Although adults are at risk from PAHs in house dust, studies have shown young children are especially vulnerable. In addition to the danger of developing cancer, emerging evidence suggests that babies who were exposed to PAHs while in the womb may be more prone to asthma and other ailments, and may have lowered IQs.

According to the USGS, once it is applied to asphalt, coal tar sealants do not stay put. The sealant slowly wears off and forms dust which is tracked into homes on the shoes of residents. In the study, conducted in Austin, Texas, researchers discovered alarming levels of PAHs in house dust in homes near parking lots and driveways coated with coal tar sealant. The PAH level in homes near coal tar sealed parking lots or driveways was at least 25 times higher than dust in comparable homes not near coal tar sealed pavement. During the study, driveway dust at two suburban homes was found to contain levels of benzo[a]pyrene, which is mutagenic and highly carcinogenic, that would have triggered a cleanup action at a toxic-waste site.

In addition to the direct human health dangers of PAHs in house dust, PAHs have been found to kill marine life and cause other adverse environmental effects in waterways near coal tar sealed pavement. This happens when particles of dirt containing dangerous levels of PAHs are deposited in nearby creeks and streams by rainwater running off parking lots coated with coal tar sealants. The cities of Austin, Texas, Washington D.C., and Madison, Wisconsin, have banned coal tar sealants after finding elevated levels of PAHs in local waterways.

Although coal tar sealants are more likely to be found in the eastern half of the United States, Congressman Lloyd Doggett (D-TX) is calling for a nationwide ban of coal tar sealants. Pavement sealants made from asphalt – rather than coal tar – are readily available, just as effective, and are a safer alternative to coal tar sealants. If you need more information on this subject you can contact Chris Boutwell, a lawyer in our firm, at 800-898-2034 or email at Chris.Boutwell@beasleyallen.com.